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LAB DISTILLATION AND SIGNIFICANCEBY

S.K. CHHIBBER1

DISTILLATION

IT is the main criteria for separating and refining of hydrocarbons. Used for the preparation of feed stock Controlling the quality of the product Preparation of pure hydrocarbons as per the requirements

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TYPES OF DISTILLATION

Non fractionating distillation (Raleigh vaporisation ) ASTM/IP distillation Equilibrium flash evaporation. Semi fractionating (Hempels,Sarina still distillation )Fractionating distillation (True boiling point ) Spinning band column3

NON FRACTAING DISTILLATION

Liquid mixture is partially vapourised and the vapour and liquid are allowed to separate. There is an increase of concentration of the more volatile components in the vapour phase and the less volatile components in the liquid phase. Vapourization effected by heating the liquid or reducing the pressure.4

RAYLEIGH`S VAPORIZATION Though

ideal but practiced rarely Flask contain sample is dipped in the thermostatic bath, the vapors formed leave the flask without coming in contact with the liquid. i.e. number of contact is just one.5

ASTM DISTILLATION-D86

IT is a std. distillation Has good repeatability/reproducibility Simple & consume less time It is used to know the boiling range of motor gasoline, aviation gasoline, special boiling point sprit, naptha,kerosene, ATF, &diesel cuts etc.

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OUT LINES OF THE METHOD

100 ml sample is taken in RB distillation flask. Heated under controlled conditions, the temperature at which 1st. Drop detached from the condenser is known as IBP.After it on every 10% distillation the temp. is recorded till highest temp. is reached & drop in temp. is observed & is known as FBP.Residue &loss during distillation is also recorded.8

ATMOSPHERIC DISTILLATION ASTM D86 / IP 123 / P18Apparatus and operating conditions Flask capacity : 125 ml Sample quantity : 100 ml Condenser temp. Depends on fuel Time for application heat IBP: 5-15 min Av. Rate of recovery : 4-5ml / min Time for 95 rec , to FBP : 3-5 min No reflux for gasoline, kerosene and diesel.9

EQUILIBRIUM FLASH VAPORISATION

To obtain EFV curve sample is heated to certain temperature and pressure to get percentage vaporized. This will give one point on EFV curve. To get other points experiments are repeated with same sample heated to different temperature but at same pressure. EFV is plotted corresponding to percentage recovered v/s temperature. Very useful design data for distillation. Co-relations to relate EFV curves with TBP & ASTM curves have been developed as it is time consuming. 10

ASTM DISTILLATION-D1160 Used

for heavy petroleum products Having max. temp.400C@1mm Hg.pressure Conditions provide one theoretical plate11

OUT LINES OF THE METHODSWeight sample corresponding to 200ml. Is taken in 500ml,RB flask, while heating vacuum between 0.5 to 10mm is maintained. Heat input is increased to get the distillation rate 4to 8 ml/min. Reading from IBP to every 10% recovery collected. FBP is recorded. These boiling ranges are converted to atmospheric equivalent tem. By Cox chart. % Recovery= %(Recovery +residue ) % Loss=100-total recovery.12

TBP DISTILLATION, D-2892It is highly fractionating distillation in which fractionating column and controlled reflux is used Equilibrium between vapors rising upwards and liquid coming downwards in a column is established. Product of better quality is obtained TBP curve establish the product pattern of various commercial products. Curve is plotted commulated%wt./vol.recovered v/s temp. For crude oil curve is normally smooth

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OUT LINES OF THE METHOD

Wt. sample 1-30 liters is distilled to 400C max under vacuum having 14-18 theoretical plate fractionating column. Reflux ratio of 5:1 through out the distillation is kept at all the operating pressure.Temp. pressure & other variables are recorded at an intervals at the end of each cut. Density & mass of each cut is obtained &yield is calculated on vol. basis as follows Vol.%= Density of feed --------------------- x% wt. Density of fraction

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TYPICAL TBP,ASTM,EFV CURVESte m p e r at u r e

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INTERCONVERSION OF DISTILLATION DATAReliability of results Maxwell method (Data book on hydrocarbons) Avg. deviation of converted to experimental 10 to 15F Ad mister method ( Applied hydrocarbon thermodynamics) At atmospheric & higher pressure ASTM TO TBP, Avg. Deviation : 7F TBP TO EFV : 6F ASTM to EFV : 9F Under sub atmospheric pressure ASTM to TBP : 5F TBP to EFV : 6F ASTM to EFV : 6F16

BOILING RANGE DISTRIBUTION BY G.CIt is simulated by GC IT is quick & less quantity of sample is required Open pack/ tubular (capillary ) GC column is used to elute the hydrocarbon components of the sample in the order of increasing boiling point.

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BOILING RANGE DISTRIBUTION BY GAS CHRONMATORAGRAPHY

ASTM 3710-97 Boiling range distribution of gasoline & gasoline fraction by G>C ASTM D2887-97 Boiling range distribution of petroleum fraction up to 538C by GC ASTM D2887 Extended High Temperature up to 615C ASTM D5307-97 Determination of boiling range distribution of crude petroleum up to 750C by GCSAMPLE

CARRIER GASCOLUMN INJECTOROV 101 SE 30 UCW - 982

INTIGRATORDECETOR

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OUT LINES OF THE METHOD

Known calibration mixture contain 20 components between C5-C42 is allowed to run in GC and retention time of each component is printed out. Retention time v/s boiling point is recorded into the microprocessor unit automatically. Unknown sample is injected & the chromatogram of area v/s retention time is printed out. The unit prints out % vol. recovery corresponding to the boiling points. If desired unit automatically convert the TBP &ASTM data too19

SIMULATED DISTILATON-D2887Typical conditions Column length 1.2m Liquid phase OV-1 SE 30, UC-W 98 Detector Temp. 350C/430C Injection port Temp. 350C Detector (FID ) Oven Temp. Int. -30C Final 350C Oven temp. program rate 10C/ min. Carrier gas Nitrogen/Helium Detector gas Hydrogen

B O I L I N G P O I N T C

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SHORT PATH DISTILLATION

Used to distill petroleum products up to 750C

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OUT LINES OF THE METHODS

Product 370+ is fed into the distillator with a constant feed rate by gear pump. It is distributed to the evaporator surface by the distribution plate at the top of the wiper basket. Forced by the gravity, the product film flows down and thereby continuous homogenized by the roller of the wiper basket. The high volatile components of the mixture are evaporated on the heated surface and afterwards condense at the internal condenser. The distillate flows down on the condenser surface to the distillate out let nozzle. The low volatile component of the mixture are not evaporated and are flowing to the residue outlet nozzle. Very high volatile component s of the mixture as well as dissolved gases are not condensed at the internal condenser. Use to distill petroleum products upto 750C.22

Hot POT Distillation apparatus

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